With a circuit arrangement, in which electronic components lie at high voltage in relation to a reference potential (e.g., ground), high electrical field strengths occur between the electronic components and the reference potential. An “electronic component” is to be understood below as an “electronic or electrical component”.
High-voltage circuit arrangements are used in x-ray generators, for example. To generate x-ray radiation, x-ray generators need an acceleration voltage, which is present as a unipolar (e.g., maximum + or −150 kV) or bipolar (e.g., symmetrical maximum −75 and +75 kV) voltage between the anode and the cathode. The high-voltage generation chain of the x-ray generator (e.g., radio-frequency or multi-pulse generator) includes, as depicted in FIG. 1, a mains power input 1, a parallel-tuned or resonant circuit inverter 2, and a high voltage generation unit 3, which provides an x-ray emitter 4 with the necessary high voltage.
High voltage generation units 3 may have an oil-filled vessel, in which one or more high-voltage transformers 5, a single-stage or multistage (e.g., cascade) rectifier circuit 6, an element for damping transient processes (e.g., resistive or inductive) and a measuring divider for determining the high voltage are arranged. Modern high voltage generators 3 have circuits that make possible a combined rectification and multiplication of the high voltage (e.g., Villard, Greinacher, Delon circuit).
The known circuits are not designed for use at high-voltage potential. If metallic tips, corners, or edges are present in high-voltage components, high field strengths will be created locally, which may exceed the electrical strength values of the surrounding insulating media. If this is the case, undesired discharges, flashovers, or sparkovers may be initiated from these points, which may lead to anything from a brief operational outage to the failure of the high voltage generator of the x-ray generator.
The published patent DE 10 2007 032 808 A1 discloses solutions for reducing the electrical field strength and adapting the parasitic capacitances of high-voltage components. In particular, it is proposed that two conducting or conductive plates be arranged at an angle to the diode chain of the high voltage generation unit on the circuit board.